You throw firebolt 10 meters away from where you actually wanted to throw it , it will still tag the enemies and do a 162 damage so who's getting rewarded for a bad grenade placement. On the other hand smoke or the grenade alone can't kill , you can just step aside and avoid it. You have to throw it directly on the target to take out atleast half of their health. Smoke + grenade is not a guranteed kill unless your grenade and smoke placement is good.